2026-10-09 APP 2.0.0-beta48 has been released !
This is mainly a bug fix release for the reported bugs in beta47. In addition it has a significant User Interface performance improvement noticable when you need to process 1000s of images in APP.
2026-10-03 APP 2.0.0-beta47 has been released !
This is a very big release... many code optimizations/rewrites, many parts of APP are much faster and more precise, especially star analysis and registration are much faster ! Big mosaics will go much faster 🙂
And we introduce a new preview filter, which includes the new Adaptive Deep Sky Stretch and a General Levels Stretch, this has been long over due. The old preview filter (the panel on the right side to stretch and preview your data) has not been updated for a couple of years and it is a critical part of any APP session.
Adaptive Deep Sky Stretch or ADSS is a much more intuitive stretch algorithm. It is also color preserving (which is a great new addition in itself ! ) which means that the highlights are no longer bleached, color is maintained from the linear data while stretching. You can simply stretch your data using the sky background level and signal width sliders which work much easier and more intuitive. You no longer need to fiddle with the old complicated sliders with zoom buttons. All the zoom buttons for the sliders are made redundant. And you can enter slider values in the slider value fields yourself. I will make a youtube video in the coming days to explain and fully introduce ADSS. Once the video is ready, it will be highlighted on the forum.
RGB Combine upgrade !. The RGB Combine Tool has been rewritten mostly. The tool is faster and easier to use and most importantly, the Luminance slider to inject a luminance channel or channels into the RGB composite is now working correctly. It no longer bleaches the RGB colors. Combined with the new ADSS preview, you will get much better and easier great composites with great color! I will also explain this in a new youtube video.
I took 140x120sec subs of IC443. I use a refractor, narrowband filter and OSC camera.
The lights were stacked with darks, flats and darkflats.
In the result I get this strange red halo.
Your help in solving the problem is much appreciated.
Thanks
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Seems like light pollution, is that a possibility in your location? Or, the flats are not correctly applied, can you see (in the list of files below) if MF is added to the filename after calibration?
@vincent-mod
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I'm in a bortle 9 location so light pollution certainly exists.
However, I usually manage to eliminate it.
MF was applied to the subs.
what do you mean by "flats are not correctly applied"?
I was wondering whether a white balanced light source is needed for the flats?
ThanksÂ
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I used a narrowband filter
Flats may not be correctly applied, not saying they are, could just be a cause of what you're seeing. However, when it indeed is light pollution, you can use the light pollution tool that should be able to take care of that nicely. Also, when using a narrowband filter, you need to set APP to extract that data properly, in tab 0 you can select to "extract Ha" for instance. This will produce an Ha, mono image, straight from the OSC data.
When you say halo, are you taking about the ring around the bright star, or are you taking about the redness in the image that seems to appear beyond the nebula, around it? If you are referring to that redness as the halo, I would say you need to do a better job cropping your image first. You can see stacking artifacts around the edges. Crop your image first, then run the LP removal and you will see much better results.
